I made some cross-linked gelatin gels and intended to use these for cell culture. To my surprise, cells like NIH3T3 or BHK 21 dont attach/spread on to these gels readily. I thought gelatin is frequently used for coating plastic culture surface to promote cell attachment.
These are glutaldehyde fixed gelatin 5% (w/v), extensively washed after blocking the reactive groups with glycine. Cells are not spreading on it after two days, most remain rounded, while they are very happy on the regular plastic dishes.
Most likely the root cause of this has to be Gluteraldehyde that is being used here. Any residual amount will interfere but technically there can be multiple reasons for it. Try the following step by step and let us know if this improves
Reduce the degree of cross-linking by lowering glutaraldehyde concentration or using a milder cross-linking agent.
Optimize the mechanical properties of the gel by adjusting gelatin concentration and cross-linking time.
Increase the number of ECM binding sites by coating the gels with fibronectin, collagen, or laminin.
Wash the gels more thoroughly to remove any residual aldehyde groups that could inhibit cell attachment.